Make a software to track response time on sent emails

I want a software that can track the response time for emails and enter the results into a mysql database. I am researching the response time for support emails for a large group of vendors, so I wish to have a tool/software that can track how long time it takes from I send out the email and until I get a response. The emails will not neccessarily be sent using this software/tool, so it needs to have the possibility to manually start the measurement. I want to be able to create different projects, and enter the data in individually. I will of course only run one project at a time, but that I can run a new project ex a week after the first one. Some of the vendors have helpdesk systems, so the ones that has that will respond with a case id email pretty quick, so the software needs to register as many mails that comes in for the next 7 days after it has started, so I think perhaps it has to be a online tool hosted on a vps or something, so that the tracking is real time.. Let me know how you intend the tool to handle the incoming mails, if it can handle pop accounts or if I should have a rackspace email with exchange functionality or how you wish to do it.. The vendors I am researching are norwegian. I will send out all the emails using a system like mailchimp or similar to ensure that they all will get delivered, or if you have any other suggestion to give me. The tool/software should also indicate in the database if it got a reply in less than 5 minutes, as that is indicative of a helpdesk system. Due to the norwegian factor it could be hard to put in triggerwords to detect the helpdesk in place, but if you got an idea here please bring it. :) Please in the bid specify which development language you intend to use on this. I wish the code to be commented so that I can learn from that later on, am studying development now.